Added test case checking type with dbref=False
Added test case checking type with dbref=False

Ensures when dbref=False the data is stored as the same type
as the primary key of the item stored. MongoEngine/mongoengine#160

DavidBord/mongoengine,reallistic/mongoengine,MongoEngine/mongoengine,MakerReduxCorp/mongoengine,cogniteev/mongoengine,ms5/mongoengine,ProgressivePlanning/mongoengine,gavincabbage/mongoengine,nicolascine/mongoengine,blaggacao/mongoengine,larsbutler/mongoengine,prijindal/mongoengine,WingGao/mongoengine,9nix00/mongoengine,Davidrjx/mongoengine,eli-b/mongoengine,closeio/mongoengine,elephanter/mongoengine,jimmyshen/mongoengine,ConsumerPhysics/mongoengine,MRigal/mongoengine,MakerReduxCorp/mongoengine,muhammad-ammar/mongoengine,starsirius/mongoengine,iandd0824/mongoengine,RussellLuo/mongoengine,nathanial/mongoengine,noirbizarre/mongoengine,gmacon/mongoengine,Multiposting/mongoengine,sourcelair/mongoengine,yarneo/mongoengine,touilleMan/mongoengine,khallaghi/mongoengine,cogniteev/mongoengine,Catstyle/mongoengine,Davidrjx/mongoengine,losintikfos/mongoengine